CVE-2026-55306 in Android
Summary
by MITRE • 09/15/2026
In Cellular Modem, there is a possible denial of service due to improper input validation. This could lead to remote denial of service with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability resides within the cellular modem subsystem and represents a critical security flaw characterized by insufficient input validation mechanisms. In modern mobile devices, the cellular modem operates as an independent processing unit that handles all radio frequency communications, including voice calls, SMS messaging, and data transmission over various network standards such as LTE and 5G NR. This component typically runs its own firmware separate from the main application processor operating system to ensure real-time performance and isolation of critical telephony functions. The flaw stems from a failure in the modem's protocol stack or control interface to properly sanitize or validate incoming signals, particularly those received during standard network attachment procedures or handover processes between cell towers. When maliciously crafted signaling messages are transmitted by an attacker-controlled base station or through a compromised network element, the modem fails to reject these invalid inputs and instead attempts to process them in a manner that exhausts available resources or causes a state machine deadlock.
This improper input validation directly facilitates a remote denial of service condition without requiring any prior authentication or elevated privileges on the target device. An attacker can exploit this weakness by simply being within radio range of the victim's device, effectively turning off their own cellular connection and broadcasting spoofed signals that mimic legitimate network commands but contain malformed data structures. Because user interaction is not required for exploitation, the attack vector is entirely passive from the perspective of the end-user, who may remain unaware that a malicious signal is being received until service disruption occurs. The lack of execution privileges needed further lowers the barrier to entry for potential attackers, allowing individuals with basic knowledge of cellular protocol analysis tools to launch effective attacks against vulnerable devices in public spaces or targeted environments.
The operational impact of this vulnerability extends beyond simple connectivity loss, affecting both individual users and enterprise networks relying on mobile broadband for critical communications. When exploited, the denial of service can manifest as a complete inability to register with any cellular network, rendering voice calls, SMS, and data services unavailable until the device is rebooted or reset to factory settings. In some implementations, repeated exploitation attempts may lead to persistent corruption of non-volatile memory storing radio configuration parameters, requiring manual intervention by technical support personnel to restore functionality. For organizations utilizing mobile devices for remote workforce operations, IoT deployments, or emergency response communications, such disruptions can result in significant productivity losses and potential safety risks if critical alerts fail to reach intended recipients. The transient nature of the attack means that while service may be restored after a reboot, the underlying vulnerability remains unpatched unless firmware updates are applied by the device manufacturer.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements within the cellular modem design. Device manufacturers should prioritize releasing security patches that enforce strict type checking and boundary validation for all incoming signaling messages at the protocol stack level. Implementing deep packet inspection capabilities within the modem firmware can help identify anomalous signal patterns indicative of exploitation attempts before they trigger resource exhaustion conditions. Additionally, adopting defense-in-depth principles by isolating critical modem processes from less secure components reduces the blast radius if a vulnerability is successfully exploited. Users should ensure their device operating systems and baseband firmware are updated to the latest versions provided by OEMs, as these updates often include hardened input validation routines addressing known flaws in protocol handling. Industry standards such as CWE-20 Improper Input Validation provide a framework for developers to systematically identify where sanitization checks are missing, while ATT&CK technique T1498 Network Denial of Service offers context on how this vulnerability fits into broader adversary tactics aimed at disrupting communications infrastructure.